Contemporary challenges in clinical pharmacy practice - medicines optimisation and medication adherence

Abstract

Optimal use of medicines is a vital step to improve the quality of care that patients receive while minimising healthcare costs. One of the top priorities in healthcare systems worldwide is to provide cost-effective healthcare and through this, to optimise healthcare resource utilisation. One of the major cost items in healthcare provision is hospitalisation and therefore the optimal use of medicines to prevent hospitalisation is a major goal. Medication adherence, one of the most important aspects in the process of optimal medicines use, unfortunately still is a major challenge in modern healthcare, and further research is required into how adherence can be assessed and optimised. The main aim of the research presented in this thesis was to carry out a series of inter-related research projects in the area of medicines optimisation, with particular emphasis on a new medicines optimisation service delivered by general practitioner (GP) practice-based pharmacists and on the management of diabetes, a chronic illness which commonly gives rise to medication use challenges. A pragmatic, prospective, multicentre, randomised intervention study to evaluate the impact of the new GP practice-based pharmacy service on patient outcomes and healthcare costs showed that this service was effective in reducing medication-related problems (median 3.0 to 0.5, p<0.001), inappropriateness of medications [median Medication Appropriateness Index score 8 to 5; p<0.001 in intention to treat (ITT) group and 7.0 to 4.0; p<0.05 in per protocol (PP) group], and the number of telephone consultations in general practice for both ITT (median 1 to 1, mean 1.9 to 1.4; p<0.05) and PP (median 1 to 1, mean 2.3 to 1.6; p<0.05) intervention groups. No significant differences between groups were found in unplanned hospital admissions, length of hospital stay, number of accident and emergency attendances or outpatient visits. Cost utility analysis showed an incremental cost per patient of -£229.0 (95% CI -594.6, 128.2) and a mean Quality-Adjusted Life Year (QALY) gained of 0.024 (95% CI -0.021 to 0.065), indicative of a health status gain at a reduced cost. A qualitative research study involving a focus group discussion and semi-structured telephone interviews with practice-based pharmacists and GPs respectively, to explore their perspectives, demonstrated that both groups were supportive of the new GP-practice based, clinical pharmacy service. A systematic content analysis was performed to evaluate how diabetes pharmacotherapy has been portrayed in highly circulated UK and US newspapers over a 10-year period (2009-2018). The analysis showed that safety/risk (34.6%), effectiveness (30.7%) and economic aspects (12.9%) were the most frequently covered topics in the newspaper articles. Almost a third (30.9%) of the total newspaper articles was deemed to present poor quality information. Finally, a multiple methods approach was used to evaluate metformin adherence in patients with type 2 diabetes. This involved self-reported questionnaires, the new approach of direct measurement of metformin concentration in dried blood spot (DBS) samples, prescribing and dispensing records, and patient interviews. The DBS sampling approach was coupled with population pharmacokinetic (PopPK) modelling, which took account of patient characteristics, metformin dosage and type of formulation prescribed (immediate or sustained release). This study demonstrated that DBS sampling together with the use of a published PopPK model was useful as a vii novel, direct, objective approach to estimate levels of adherence in adult patients with type 2 diabetes. The proportion of patients considered overall (combined) adherent to metformin, derived from self-reported Medication Adherence Report Scales (MARS) scores and metformin concentration in DBS samples, was 61.2% (74 out of 121 patients). From the overall non-adherent patients (n=47), 19 patients were deemed to be over-adherent (had metformin levels higher than the predicted plasma concentrations). Metformin self-administration and use of a purchased adherence pill box significantly increased the probability of a patient being non-adherent based on logistic regression analysis. Optimal medication use, including good medication adherence remain significant challenges in clinical pharmacy practice. The present research demonstrates the value of conducting careful, pragmatic research which examines the impact of new service provision and indeed develops new approaches to assess adherence within the busy clinical environment.

Date of Award	Dec 2020
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Indonesia Endowment Fund for Education (Lembaga Pengelola Dana Pendidikan/LPDP) Scholarship
Supervisor	Carole Parsons (Supervisor), James McElnay (Supervisor) & Michael Scott (Supervisor)